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The X1288 device is a Real Time Clock with clock/calendar, two polled alarms with integrated 32kx8 EEPROM, oscillator compensation, CPU Supervisor (POR/LVS and WDT) and battery backup switch.

The oscillator uses an external, low-cost 32.768kHz crystal. All compensation and trim components are integrated on the chip. This eliminates several external discrete components and a trim capacitor, saving board area and component cost.

The Real-Time Clock keeps track of time with separate registers for Hours, Minutes, Seconds and 1/100 of a second. The Calendar has separate registers for Date, Month, Year and Day-of-week. The calendar is correct through 2099, with automatic leap year correction.

The powerful Dual Alarms can be set to any Clock/Calendar value for a match. For instance, every minute, every Tuesday, or 5:23 AM on March 21. The alarms can be polled in the Status Register or provide a hardware interrupt (IRQ Pin). There is a repeat mode for the alarms allowing a periodic interrupt.

The PHZ/IRQ pin may be software selected to provide a frequency output of 1 Hz, 100 Hz, or 32,768 Hz.

The X1288 device integrates CPU Supervisor func-tions and a Battery Switch. There is a Power-On Reset (RESET output) with typically 250 ms delay from poweron. It will also assert RESET when Vcc goes below the specified threshold. The Vtrip threshold is user reprogrammable.

There is a WatchDog Timer (WDT) with 3 selectable time-out periods (0.25s, 0.75s, 1.75s) and a disabled setting. The watchdog activates the RESET pin when it expires

Key Features

• Real Time Clock/Calendar
  • Tracks time in Hours, Minutes, Seconds and Hundredths of a Second
  • Day of the Week, Day, Month, and Year
• 2 Polled Alarms (Non-volatile)
  • Settable on the Second, Minute, Hour, Day of the Week, Day, or Month
  • Repeat Mode (periodic interrupts)
• Oscillator Compensation on chip
  • Internal feedback resistor and compensation capacitors
  • 64 position Digitally Controlled Trim Capacitor
  • 6 digital-frequency adjustment setting to ±30ppm
• CPU Supervisor Functions
  • Power-on Reset, Low Voltage Sense
  • Watchdog Timer (SW Selectable: 0.25s, 0.75s, 1.75s, off)
• Battery Switch or Super Cap Input
• 32K x 8 Bits of EEPROM
  • 128-Byte Page Write Mode
  • 8 modes of Block Lock™ Protection
  • Single Byte Write Capability
• High Reliability
  • Data Retention: 100 years
  • Endurance: 100,000 cycles per byte
• 2-Wire™ Interface interoperable with I2C* - 400kHz data transfer rate
• Frequency Output (SW Selectable: Off, 1Hz, 100Hz, or 32.768kHz)
• Low Power CMOS
  • 1.25µA Operating Current (Typical)
• Small Package Options
  • 16-Lead SOIC and 14-Lead TSSOP
• Pb-Free Plus Anneal Available (RoHS Compliant)

Applications

• Utility Meters
• HVAC Equipment
• Audio/Video Components
• Set Top Box/Television
• Modems
• Network Routers, Hubs, Switches, Bridges
• Cellular Infrastructure Equipment
• Fixed Broadband Wireless Equipment
• Pagers/PDA
• POS Equipment
• Test Meters/Fixtures
• Office Automation (Copiers, Fax)
• Home Appliances
• Computer Products
• Other Industrial/Medical/Automotive